It is a little concerning to me how much smoke seems to be coming off of the landing legs for most of the flight. Makes me wonder about what kind of thermal protection they have, or if the legs and other sections near the bottom of the rocket will need to be replaced frequently. I'm sure when it comes to the total cost saved from recovering the rocket the cost of replacing the legs and other bits is pretty insignificant, but it could make for a situation in the future where the launch schedule is constrained by their production.

It is a little concerning to me how much smoke seems to be coming off of the landing legs for most of the flight. Makes me wonder about what kind of thermal protection they have, or if the legs and other sections near the bottom of the rocket will need to be replaced frequently. I'm sure when it comes to the total cost saved from recovering the rocket the cost of replacing the legs and other bits is pretty insignificant, but it could make for a situation in the future where the launch schedule is constrained by their production.

Click to expand...

The good thing is that this is the testing vehicle. They can discover whether the legs are damaged in any critical way during the landing and, in this case, the take off as well. My interpretation is that there was a lot fire and smoke coming off the legs at takeoff. I'd bet those legs had something flammable on them like paint or fuel that burned off during the initial launch. By the time the rocket was coming in for a landing whatever it was seemed to have completely burned off.

I suspect that the shrouds on the legs serve a twofold purpose: 1) To act as aerodynamic fairings during the launch and journey to hyper-sonic speeds, and 2) to provide thermal protection for the actual struts of the legs underneath (which appear to be either hydraulic or pneumatic cylinders) during the landing.

Thus it would not surprise me if they are designed to be either ablative, or perhaps disposable all together.

The shrouds bear a pulling force, whereas the telescopic struts bear a pushing force. If one of the shrouds snaps at touch down, the rocket booster likely will topple over. It is crucial that they are designed to withstand the thermal exposure until the rocket is secured.

Agreed.... I'm simply suggesting that they are designed to deal with the heat, and as they themselves are not the units with the cylinder assembly portion of the legs they may even have a sacrificial/ablative coating on them in addition to whatever paint is burngin off..

On this topic, I wonder jsut how much issue they are experiencing in terms of heat? Obviously, something is burning, but I haven't seen any info indicating how serious, if at all it is.

I would think if they were really having problems, they could try some sort of two stage deployment of the legs, The first setting increases drag and aids in stabilization, and the second setting is used for the actual landing.

I'm going to peruse the NSF forum tonight to see what those folks have to say.